236 lines
6.8 KiB
C
236 lines
6.8 KiB
C
/*
|
|
* arch/v850/kernel/ptrace.c -- `ptrace' system call
|
|
*
|
|
* Copyright (C) 2002,03,04 NEC Electronics Corporation
|
|
* Copyright (C) 2002,03,04 Miles Bader <miles@gnu.org>
|
|
*
|
|
* Derived from arch/mips/kernel/ptrace.c:
|
|
*
|
|
* Copyright (C) 1992 Ross Biro
|
|
* Copyright (C) Linus Torvalds
|
|
* Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
|
|
* Copyright (C) 1996 David S. Miller
|
|
* Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
|
|
* Copyright (C) 1999 MIPS Technologies, Inc.
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General
|
|
* Public License. See the file COPYING in the main directory of this
|
|
* archive for more details.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/signal.h>
|
|
|
|
#include <asm/errno.h>
|
|
#include <asm/ptrace.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
/* Returns the address where the register at REG_OFFS in P is stashed away. */
|
|
static v850_reg_t *reg_save_addr (unsigned reg_offs, struct task_struct *t)
|
|
{
|
|
struct pt_regs *regs;
|
|
|
|
/* Three basic cases:
|
|
|
|
(1) A register normally saved before calling the scheduler, is
|
|
available in the kernel entry pt_regs structure at the top
|
|
of the kernel stack. The kernel trap/irq exit path takes
|
|
care to save/restore almost all registers for ptrace'd
|
|
processes.
|
|
|
|
(2) A call-clobbered register, where the process P entered the
|
|
kernel via [syscall] trap, is not stored anywhere; that's
|
|
OK, because such registers are not expected to be preserved
|
|
when the trap returns anyway (so we don't actually bother to
|
|
test for this case).
|
|
|
|
(3) A few registers not used at all by the kernel, and so
|
|
normally never saved except by context-switches, are in the
|
|
context switch state. */
|
|
|
|
if (reg_offs == PT_CTPC || reg_offs == PT_CTPSW || reg_offs == PT_CTBP)
|
|
/* Register saved during context switch. */
|
|
regs = thread_saved_regs (t);
|
|
else
|
|
/* Register saved during kernel entry (or not available). */
|
|
regs = task_pt_regs (t);
|
|
|
|
return (v850_reg_t *)((char *)regs + reg_offs);
|
|
}
|
|
|
|
/* Set the bits SET and clear the bits CLEAR in the v850e DIR
|
|
(`debug information register'). Returns the new value of DIR. */
|
|
static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear)
|
|
{
|
|
register v850_reg_t rval asm ("r10");
|
|
register v850_reg_t arg0 asm ("r6") = set;
|
|
register v850_reg_t arg1 asm ("r7") = clear;
|
|
|
|
/* The dbtrap handler has exactly this functionality when called
|
|
from kernel mode. 0xf840 is a `dbtrap' insn. */
|
|
asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1));
|
|
|
|
return rval;
|
|
}
|
|
|
|
/* Makes sure hardware single-stepping is (globally) enabled.
|
|
Returns true if successful. */
|
|
static inline int enable_single_stepping (void)
|
|
{
|
|
static int enabled = 0; /* Remember whether we already did it. */
|
|
if (! enabled) {
|
|
/* Turn on the SE (`single-step enable') bit, 0x100, in the
|
|
DIR (`debug information register'). This may fail if a
|
|
processor doesn't support it or something. We also try
|
|
to clear bit 0x40 (`INI'), which is necessary to use the
|
|
debug stuff on the v850e2; on the v850e, clearing 0x40
|
|
shouldn't cause any problem. */
|
|
v850_reg_t dir = set_dir (0x100, 0x40);
|
|
/* Make sure it really got set. */
|
|
if (dir & 0x100)
|
|
enabled = 1;
|
|
}
|
|
return enabled;
|
|
}
|
|
|
|
/* Try to set CHILD's single-step flag to VAL. Returns true if successful. */
|
|
static int set_single_step (struct task_struct *t, int val)
|
|
{
|
|
v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t);
|
|
if (val) {
|
|
/* Make sure single-stepping is enabled. */
|
|
if (! enable_single_stepping ())
|
|
return 0;
|
|
/* Set T's single-step flag. */
|
|
*psw_addr |= 0x800;
|
|
} else
|
|
*psw_addr &= ~0x800;
|
|
return 1;
|
|
}
|
|
|
|
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
|
|
{
|
|
int rval;
|
|
|
|
switch (request) {
|
|
unsigned long val;
|
|
|
|
case PTRACE_PEEKTEXT: /* read word at location addr. */
|
|
case PTRACE_PEEKDATA:
|
|
rval = generic_ptrace_peekdata(child, addr, data);
|
|
goto out;
|
|
|
|
case PTRACE_POKETEXT: /* write the word at location addr. */
|
|
case PTRACE_POKEDATA:
|
|
rval = generic_ptrace_pokedata(child, addr, data);
|
|
goto out;
|
|
|
|
/* Read/write the word at location ADDR in the registers. */
|
|
case PTRACE_PEEKUSR:
|
|
case PTRACE_POKEUSR:
|
|
rval = 0;
|
|
if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
|
|
/* Special requests that don't actually correspond
|
|
to offsets in struct pt_regs. */
|
|
if (addr == PT_TEXT_ADDR)
|
|
val = child->mm->start_code;
|
|
else if (addr == PT_DATA_ADDR)
|
|
val = child->mm->start_data;
|
|
else if (addr == PT_TEXT_LEN)
|
|
val = child->mm->end_code
|
|
- child->mm->start_code;
|
|
else
|
|
rval = -EIO;
|
|
} else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) {
|
|
v850_reg_t *reg_addr = reg_save_addr(addr, child);
|
|
if (request == PTRACE_PEEKUSR)
|
|
val = *reg_addr;
|
|
else
|
|
*reg_addr = data;
|
|
} else
|
|
rval = -EIO;
|
|
|
|
if (rval == 0 && request == PTRACE_PEEKUSR)
|
|
rval = put_user (val, (unsigned long *)data);
|
|
goto out;
|
|
|
|
/* Continue and stop at next (return from) syscall */
|
|
case PTRACE_SYSCALL:
|
|
/* Restart after a signal. */
|
|
case PTRACE_CONT:
|
|
/* Execute a single instruction. */
|
|
case PTRACE_SINGLESTEP:
|
|
rval = -EIO;
|
|
if (!valid_signal(data))
|
|
break;
|
|
|
|
/* Turn CHILD's single-step flag on or off. */
|
|
if (! set_single_step (child, request == PTRACE_SINGLESTEP))
|
|
break;
|
|
|
|
if (request == PTRACE_SYSCALL)
|
|
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
else
|
|
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
|
|
child->exit_code = data;
|
|
wake_up_process(child);
|
|
rval = 0;
|
|
break;
|
|
|
|
/*
|
|
* make the child exit. Best I can do is send it a sigkill.
|
|
* perhaps it should be put in the status that it wants to
|
|
* exit.
|
|
*/
|
|
case PTRACE_KILL:
|
|
rval = 0;
|
|
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
|
|
break;
|
|
child->exit_code = SIGKILL;
|
|
wake_up_process(child);
|
|
break;
|
|
|
|
case PTRACE_DETACH: /* detach a process that was attached. */
|
|
set_single_step (child, 0); /* Clear single-step flag */
|
|
rval = ptrace_detach(child, data);
|
|
break;
|
|
|
|
default:
|
|
rval = -EIO;
|
|
goto out;
|
|
}
|
|
out:
|
|
return rval;
|
|
}
|
|
|
|
asmlinkage void syscall_trace(void)
|
|
{
|
|
if (!test_thread_flag(TIF_SYSCALL_TRACE))
|
|
return;
|
|
if (!(current->ptrace & PT_PTRACED))
|
|
return;
|
|
/* The 0x80 provides a way for the tracing parent to distinguish
|
|
between a syscall stop and SIGTRAP delivery */
|
|
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
|
|
? 0x80 : 0));
|
|
/*
|
|
* this isn't the same as continuing with a signal, but it will do
|
|
* for normal use. strace only continues with a signal if the
|
|
* stopping signal is not SIGTRAP. -brl
|
|
*/
|
|
if (current->exit_code) {
|
|
send_sig(current->exit_code, current, 1);
|
|
current->exit_code = 0;
|
|
}
|
|
}
|
|
|
|
void ptrace_disable (struct task_struct *child)
|
|
{
|
|
/* nothing to do */
|
|
}
|